M79 is an intriguing eighth magnitude globular cluster located in the constellation of Lepus. At a distance of 41,000 light-years from Earth and 60,000 light-years from the Milky Way centre, it's believed to be an extragalactic globular and a native of the nearby Canis Major Dwarf galaxy. The only other extragalactic globular cluster in Messiers catalogue is M54, which belongs to the Sagittarius Dwarf Elliptical galaxy.
Unusual for globulars, M79 is located opposite the galactic center and therefore best seen during the Southern Hemisphere summer and Northern Hemisphere winter months. With a declination of -24.5 degrees south it never rises particular high above the southern horizon from northern temperate latitudes. However, it's one of the finest globulars that can be seen during this time of year.
The constellation of Lepus is located south of Orion and west of Canis Major. It contains few deep sky objects within the range of amateur scopes and M79 is the only Messier object found within its boundaries. Locating M79 is easy; its positioned 20 degrees southwest of Sirius (α CMa - mag. -1.46), the brightest star in the night sky. An imaginary line connecting Arneb (α Lep - mag. +2.6) with Nihal (β Lep - mag. +2.8) and extending southwards for about the same distance again leads to M79. About 0.5 degrees southwest of M79 lies the magnitude +5.1 double star HD 35162 (HIP 25045) with its 7th magnitude companion, separated by 3 arc minutes.
At magnitude +8.1, M79 is visible as a fuzzy spot through 7x50 or 10x50 binoculars. A small 80mm (3.1-inch) telescope reveals the cluster as a somewhat yellow looking unresolved hazy comet-like ball of light. It has a bright core and therefore stands up well to light polluted skies and a certain amount of moonlight. Larger scopes of minimum 250mm (10-inch) aperture are required to begin resolution of the outer edges.
In total M79 spans 8.7 arc minutes in diameter, which corresponds to a spatial diameter of 104 light-years. The globular contains 150,000 stars and is estimated to be 11.7 billion years old.
M79 Data Table
|Object Type||Globular cluster|
|RA (J2000)||05h 24m 11s|
|DEC (J2000)||-24d 31m 27s|
|Apparent Size (arc mins)||8.7 x 8.7|
|Number of Stars||150,000|
|Notable Feature||Likely belongs to the Canis Major Dwarf Galaxy|